题解 | #牛的奶量统计II#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @param targetSum int整型 
     * @return bool布尔型
     */
    public static boolean result = false;
    public boolean hasPathSumII (TreeNode root, int targetSum) {
        // write code here
        if(root == null){
            return result;
        }

        search(root,root.val,targetSum);
        return result;
    }

    public void search(TreeNode root,int sum,int targetSum){
        if(sum == targetSum){
            result = true;
            return;
        }

        // 当大于目标值时后续便不再满足
        if((root.left == null && root.right == null) || targetSum < sum){
            return;
        }

        if(root.left != null){
            search(root.left,sum + root.left.val,targetSum);
            // 任意节点到任意子节点满足
            search(root.left,0,targetSum);
        }
        
        if(root.right != null && result == false){
            search(root.right,sum + root.right.val,targetSum);
            // 任意节点到任意子节点满足
            search(root.right,0,targetSum);
        }
    }
}